Which BBC star pocketed £1.5m last year? Which of Auntie's high-profile journalists scoops an extra £20,000 – on top of their six-figure pay packet – for every documentary they front for the BBC? And how much do we, the licence fee payers, pay Jeremy Clarkson to insult the populations of developing nations across the globe?

None of these questions will be answered by the BBC. Mark Thompson, the director general, has steadfastly refused to reveal star salaries, citing fears that publication will lead to inflation. "You release all this information … actually the danger is the price goes up," he told one of his highly-paid presenters, Andrew Marr, on BBC1 last year.

But MediaGuardian can reveal the scale of salaries paid to stars at the broadcaster, in figures drawn from internal BBC data, company documents, and the insights of senior sources at the corporation. The disclosures come ahead of a landmark announcement next week, when the BBC will release the most detailed breakdown in its history of the contracts awarded to its top talent. There will be no names, but the BBC annual report, published on 12 July, will tell viewers for the first time the number of stars who fall within certain salary bands.

Licence fee freeze

The corporation has adopted a series of brackets recommended by the culture, media and sport select committee, beginning at £0-£50,000, and topping out at a £5m-plus band. Since the departure of Jonathan Ross and his mythical £6m-a-year pay packet, there are no performers in the highest group. Instead, the headline will be that the corporation paid 19 actors, presenters and journalists more than £500,000 each in the 12 months to the end of March.

The figure is down from 21 in the previous year, as a chastened BBC tries to live within the means imposed by a six-year licence fee freeze. According to the accounts, total spending on talent will fall for the second consecutive year, this time by 4%, from £222m to £213m. Ignoring the bit-part performers, the cost of all those paid more than £100,000 will also drop, from £68m to £65m.

The biggest fall, however, will come from cuts to the megastars, those performers paid more than £1m. The departure of Adrian Chiles to ITV, along with his fellow One Show host, Christine Bleakley, has contributed to a £2.3m fall in the total paid to those on more than £1m, which now amounts to around £14.5m. But the corporation will not reveal how many stars it has on seven-figure salaries, as its legal advisers say that the number is low enough to provoke a public guessing game that will allow jigsaw identification, putting it in breach of its confidentiality requirements. It will instead reveal only an aggregated number for all of those on more than £500,000.

Critics will say that the BBC will do anything to obscure how many stars earn salaries that cross the psychologically important £1m barrier. In truth, the guessing game has gone on in the pages of the tabloid newspapers for years. Talent agents say the sort of figures that appear – £1.5m for Gary Lineker, or £1m for Alan Hansen, the same for Anne Robinson – are grossly inflated, but those who have seen the figures concede that there are at least a handful of stars being paid top dollar.

Chris Evans, whose introduction to the The One Show sofa on Fridays led to Chiles's departure, is understood to have recently negotiated a pan-BBC deal taking in his TV work and his Radio 2 breakfast show. He is thought to have agreed a pay cut in return for a longer deal – although his salary still stands above £1m.

Jeremy Paxman, another ever-present in the speculative list of top earners, is thought to be on a £750,000 deal covering Newsnight and University Challenge. On top of this, however, he earns an extra £20,000 in what is known as a "presenter bonus" for each documentary he fronts. The forthcoming five-part Empire series, to be screened on BBC1 in the autumn, will net him an extra £100,000.

Aside from Paxman, other areas of the BBC's news department are picked upon by both internal and external critics as overpaying for talent. A leaked pay slip belonging to Marr, which suggested the former BBC political editor earns £600,000, was seized upon by rivals as an example of largesse. Tom Bradby, ITV News's political editor, wrote at the time: "No one in ITV News is paid anything like this."

ITN, which produces news for both ITV and Channel 4, complains that the BBC's news operation suffers from "an inflated internal market".

In entertainment, those with their hands on the budgets say there are some general rules. No one on BBC1 on Saturday night earns more than £35,000 per show – with the exception of Bruce Forsyth, who is thought to be paid around £40,000 for each appearance on Strictly Come Dancing, putting his annual pay packet at just less than £500,000.

The £35,000 cap may seem high from the outside, but it hampers the BBC. BSkyB, which has pledged to use its financial muscle to increase its content spending by 50%, can easily outbid the corporation. James Corden, catapulted to fame by the BBC, jumped to Sky1 to rake in £65,000 per episode of his panel show, A League Of Their Own. David Walliams is understood to pocket £50,000 per episode of Wall of Fame, also on Sky1.

Freelance basis

But aside from the unofficial reports there are some cases where there are publicly available clues. In recent years many of the top stars have formed their own service companies, through which they work for the BBC on a freelance basis. It is a tax-efficient arrangement that benefits both the BBC and the performer. The downside is that they must file public accounts at Companies House, although most performers run entities that are small enough to publish abbreviated filings, in which they must show only the bank balance of the company, but not how much money it earned.

Saviour Productions, operated by Radio 1 breakfast show host Chris Moyles, who signed a £1m deal on Friday keeping him at the BBC until 2014,has £628,000 cash in the bank, according to the company's balance sheet. Fiona Bruce, who is reputed to earn upwards of £500,000 for her roles as newsreader and Antiques Roadshow presenter, has £436,000 in the bank account of her company, Paradox Productions.

Graham Norton, who is thought to be the best-paid BBC presenter, owns 50% of So Television, the production company that makes his BBC1 chat show. The Eurovision host also channels his BBC fees through So, which has transparent accounting arrangements. In its 2010 accounts So Television states that Norton was paid £1.5m in fees and royalties, plus a £500,000 dividend. Those close to the star say that the larger figure is his BBC talent fee, while the dividend is his share of production profits.

All three presenters of Top Gear also operate their own companies. Richard Hammond, whose flourishing BBC career is thought to have pushed him into the £1m-plus league, has a staggering £1.6m cash at bank with his company, Hamster's Wheel Productions. James May's service company, Blockhead & May, banks with Coutts, but is not quite in the same league as Hammond. May has, however, published more detailed accounts, declaring in the company's 2009 filings that the company had revenues of £637,000, of which he paid himself a dividend of £382,000.

But how much of the licence fee does Clarkson trouser? A lot less than many people think. Those who have seen the figures say he takes home less than £500,000 from the licence fee. Instead, the bulk of his earnings are channelled through the corporation's commercial arm, BBC Worldwide, as part of a deal struck in 2008 that grants Clarkson nearly 30% of profits generated by the sale of Top Gear to foreign broadcasters, along with merchandise.

Top Gear is the BBC's most successful foreign export, and generates £33m a year for Worldwide, according to the 2010 accounts of Bedder 6, the service company in which Clarkson and the show's executive producer, Andy Wilman, have a stake. Clarkson was paid £854,000 by the company last year, according to its accounts, on top of his BBC salary. Wilman, thought to be the best-paid producer at the BBC, whose income from the licence fee is topped up with payments of £396,000 from the commercial arm.

Ironically, it was Sir Michael Lyons (pictured below), pilloried while serving as the first chairman of the BBC Trust for being too soft on management, who advanced the strongest internal case for greater transparency.

A year ago, Lyons circulated a speech in advance in which he said the corporation needed to "recapture public confidence" on talent pay, and "should release the names of those who receive the biggest incomes from the BBC". Thompson's apparatchiks shot the idea down, forcing Lyons to moderate the text. In the end, the notion fizzled out.

His replacement, the Conservative peer Lord Patten, has already backed Thompson's view, insisting that any desire to have names published alongside salaries is nothing more than "prurience". So there is no internal appetite for greater detail. Perhaps the more pertinent point, then, remains whether it is in the BBC's interest to continue to withhold publication of the exact pay packets of the Nortons and Paxmans.

The situation is very different in Ireland where Emily O'Reilly, the information commissioner, demolished every argument advanced by RTE, that nation's licence-fee funded broadcaster, as to why it should not have to divulge the salaries paid to its highest-paid presenters. Since that verdict was handed down, seven years ago, RTE has voluntarily published on an annual basis the names and salaries of its top 10 stars – down to the last euro. It says that transparency is worth the pain.

Thompson's opposition to full talent disclosure is rooted in a belief that publishing the exact figures would ultimately secure worse value for money for licence fee payers; that the numbers are of interest to the public, but not in the public interest. Inflation is the argument. If the BBC's rivals know what it is paying Norton, they can easily outbid the corporation, forcing it in turn to raise its offer.

In Ireland, O'Reilly says: "The question of presenters comparing salaries could arise at any stage, given that they are generally free to disclose their salary details at any time, either to each other or to the world at large."